Generally, a battery and a capacitor are a typical device for storing electrical energy.
An ultra capacitor, also known as a super capacitor, has intermediate characteristics between an electrolytic condenser and a secondary battery, and due to high efficiency and semi-permanent life characteristics, is considered the next-generation energy storage device as an alternative to a secondary battery or usable in combination with a secondary battery.
In the application of an ultra capacitor, a high voltage module of several thousands of Farads (F) or several hundreds of voltages V is needed for use as a high voltage battery. A high voltage module is implemented as a high voltage ultra capacity assembly including as many ultra capacitors, also called unit cells, as needed connected in series. In this instance, the high voltage ultra capacity assembly is made by connecting the plurality of ultra capacitors by a busbar and fastening them with a nut.
However, the foregoing-structured ultra capacity assembly needs a plurality of busbars and nuts to connect a plurality of ultra capacitors. For example, to connect three ultra capacitors in series, one busbar and two nuts are needed to connect an anode terminal of a first ultra capacitor to a cathode terminal of a second ultra capacitor. Also, one busbar and two nuts are needed to connect an anode terminal of the second ultra capacity to a cathode terminal of a third ultra capacitor. Thus, to connect three ultra capacitors in series, two busbars and four nuts are needed in total. That is, to connect N ultra capacitors, N−1 busbars and 2*(N−1) nuts are needed.
This ultra capacitor module has a drawback in that as the number of ultra capacitors connected in series increases, production costs rise and product assembly operations increase in number with the increasing number of components. Also, since the entire connecting structure increases in resistance due to the presence of the contact resistance between the busbar and the ultra capacitor, there is a problem of a large amount of heat being generated.
Also, the high voltage ultra capacitor module made by connecting in series is susceptible to cell voltage imbalance during charge, standby or discharge due to a characteristic parameter difference. Through this, cell aging is accelerated and the life of the module is shortened, for example, a capacity of a state of charge (SOC) of the module is reduced. Also, in some cases, a certain cell may break down or explode due to its overvoltage.
Generally, a balancing board having a balancing function controls the cell voltage by connecting to a harness and a bolting part formed on an outer surface of a nut connecting adjacent cells.
However, the above-mentioned configuration has a disadvantage in that production costs are subject to increase due to an additional process of forming the bolting part on the nut. Also to ease the connection of the harness connecting the bolting part and the balancing board, the bolting part must run in a fixed direction; however, there is a drawback in that it is difficult to fix the bolting part in one direction.
Also, there is a disadvantage in that a separate structure is needed to fix the balancing board.